When a workpiece is cut by laser machining, it is conventional to use a method of forming a through hole at a cutting start point on the workpiece prior to starting the cutting. The through hole is called a piercing hole, which is formed by machining called piercing.
Patent Literature 1 discloses a laser machining method that inhibits the oxidation/combustion reaction during piercing, reduces the amount of molten metal scattering, and forms the piercing hole in a short period of time by performing piercing that includes a first process of irradiating a workpiece with a beam under a first condition, a second process of suspending irradiation with the beam, and a third process of re-irradiating the workpiece with the beam under a second condition.